Orchid Potting Mix --- Hydrocorn, Coconut Husk Chips, Charcoal. 1/4 Cubic Foot Bag. Hydrocorn (expanded clay pellets), Coconut Husk Chips with Charcoal. 1/4 Cubic Foot Bag. Popular all around general purpose orchid potting medium. We recommend soaking mix before repotting. Will store for years if put away dry. Hydrocorn .3 - .5 inch. Coconut husk chips .5 inch. Charcoal .5 inch. All plus/minus. Jim's orchid supplies offers a wide variety of orchid growing supplies including quality orchid potting mediums: